Commit aefb9256 authored by Matt Caswell's avatar Matt Caswell
Browse files

Don't attempt to send fragments > max_send_fragment in DTLS 



We were allocating the write buffer based on the size of max_send_fragment,
but ignoring it when writing data. We should fragment handshake messages
if they exceed max_send_fragment and reject application data writes that
are too large.

Reviewed-by: default avatarRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3286)
parent bd79bcb4

include/openssl/ssl.h

+1 −0
Original line number Diff line number Diff line
@@ -2607,6 +2607,7 @@ int ERR_load_SSL_strings(void); 
# define SSL_R_ENCRYPTED_LENGTH_TOO_LONG                  150

# define SSL_R_ERROR_IN_RECEIVED_CIPHER_LIST              151

# define SSL_R_ERROR_SETTING_TLSA_BASE_DOMAIN             204

# define SSL_R_EXCEEDS_MAX_FRAGMENT_SIZE                  194

# define SSL_R_EXCESSIVE_MESSAGE_SIZE                     152

# define SSL_R_EXTRA_DATA_IN_MESSAGE                      153

# define SSL_R_EXT_LENGTH_MISMATCH                        163

ssl/record/rec_layer_d1.c

+5 −0
Original line number Diff line number Diff line
@@ -882,6 +882,11 @@ int do_dtls1_write(SSL *s, int type, const unsigned char *buf, 
    if (len == 0 && !create_empty_fragment)

        return 0;



    if (len > s->max_send_fragment) {

        SSLerr(SSL_F_DO_DTLS1_WRITE, SSL_R_EXCEEDS_MAX_FRAGMENT_SIZE);

        return 0;

    }



    sess = s->session;



    if ((sess == NULL) ||

ssl/ssl_err.c

+2 −0
Original line number Diff line number Diff line
@@ -590,6 +590,8 @@ static ERR_STRING_DATA SSL_str_reasons[] = { 
     "error in received cipher list"},

    {ERR_REASON(SSL_R_ERROR_SETTING_TLSA_BASE_DOMAIN),

     "error setting tlsa base domain"},

    {ERR_REASON(SSL_R_EXCEEDS_MAX_FRAGMENT_SIZE),

     "exceeds max fragment size"},

    {ERR_REASON(SSL_R_EXCESSIVE_MESSAGE_SIZE), "excessive message size"},

    {ERR_REASON(SSL_R_EXTRA_DATA_IN_MESSAGE), "extra data in message"},

    {ERR_REASON(SSL_R_EXT_LENGTH_MISMATCH), "ext length mismatch"},

ssl/statem/statem_dtls.c

+3 −0
Original line number Diff line number Diff line
@@ -214,6 +214,9 @@ int dtls1_do_write(SSL *s, int type) 
        else

            len = s->init_num;



        if (len > s->max_send_fragment)

            len = s->max_send_fragment;



        /*

         * XDTLS: this function is too long.  split out the CCS part

         */